Effect of prolonged administration of low doses of dietary retinoids on cell-mediated immunity and the growth of transplantable tumors in mice

A study was conducted on the activity exerted by prolonged dietary supplementation with progressive amounts of retinoids on cell-mediated immune responses and the growth of transplantable tumors in mice. A few groups of BALB/c mice received 0 (group C), 50 (group A 50), 200 (group A 200), 500 (group A 500), and 1,000 (group A 1000) IU retinol palmitate/mouse/day in drinking water for 150 days. At progressive intervals mice from each group were tested for proliferative responses to concanavalin A (Con A), Escherichia coli lipopolysaccharide, interleukin-2, and interferon-gamma release to Con A. Ten mice from each group were also challenged with the 90-100% tumor-inducing dose of 3 distinct transplantable tumors. At the end of the experiment the principal organs were histologically examined, and the accumulation of vitamin A was evaluated. In groups A 200, A 500, and A 1000, an increase in the proliferative responses and production of lymphokines as compared to those in group C occurred after 60-90 days, but vanished after 150 days. The takes of the 3 tumors were impaired when the challenges were performed on days 75 and 150. This enhancement of distinct functions of cellular reactivity and resistance to transplantable tumors showed a linear relationship with the amount of supplemental retinol palmitate for the first 60-90 days. After 150 days, however, these enhancement effects vanished or tended to decrease.

[Microbiological-clinical study on the efficacy of a new antibiotic: teicoplanin]

Teicoplanin is a new antibiotic isolated from the fermentation broth of Actinoplanes teichomyceticus nov. sp. It's a glycopeptide antibiotic belonging to the same family as vancomycin, active against Gram-positive bacteria. The antimicrobial activity of this drug was evaluated in 32 patients suffering from different infections due to Gram-positive bacteria. Among the 36 Gram-positive microorganisms isolated, 15 staphylococci were methicillin resistant, 10 were sensitive, 1 was intermediate and for another one the methicillin susceptibility was not evaluated. After the treatment with teicoplanin, cure and improvement occurred in 26 cases (81%), in 2 cases the therapy failed (6%), in 2 cases there was a relapse and 2 cases were not evaluable. From this clinical study Teicoplanin results safe and effective in the therapy of Gram-positive infections.

Adhesion of Proteus species to various cell types

Pathogenic and saprophytic Proteus strains from the urine of patients with urinary tract infections and healthy adults respectively were evaluated with regard to their ability to adhere in vitro to homologous cells (uroepithelial cells from urinary sediment and cultured WISH cells) and heterologous cells (RK-13 and MDCK cells). The effect on attachment of pretreating bacteria with subinhibitory concentrations of piperacillin and sagamicin was also determined for one sensitive and one resistant strain. Fifty percent of the pathogenic Proteus strains demonstrated good adherence to human urinary epithelial cells, whereas saprophytic strains did not adhere. There was a lower rate of attachment to culture cells. Piperacillin and sagamicin in subinhibitory concentrations caused a decrease in the attachment of the sensitive Proteus strain.

Natural macrophage cytotoxicity against Trichomonas vaginalis is mediated by soluble lytic factors

Mechanisms of lysis of the extracellular protozoan Trichomonas vaginalis by uninduced resident macrophages were analyzed. Supernatants obtained by culturing such macrophages with T. vaginalis were cytotoxic for the protozoa in a dose-dependent manner. Supernatants from macrophages cultured alone were cytotoxic at lower levels, whereas those obtained from T. vaginalis alone and from macrophages cultured with unrelated cells (B77) were not cytotoxic. Cytotoxic activity appeared after 4 h of contact between effectors and target cells and reached a plateau at 18 to 24 h. Microtubule disrupting agents (colchicine and vinblastine) enhanced protozoan lysis, whereas cytochalasin B, an inhibitor of microfilaments, completely blocked T. vaginalis lysis. Treatment of macrophages with protein synthesis inhibitors (cycloheximide and puromycin) impaired effector cytotoxicity. Lytic activity remained after dialysis of supernatants, treatment with 10% bovine fetal serum, and treatment at 56 degrees C for 1 h, but it was completely prevented by treatment at 90 degrees C for 10 min. In conclusion, our data show that natural cytotoxicity against T. vaginalis is performed by normal resident macrophages through the release of at least two heterogeneous soluble factors.

Comparison between five methods for the separation of IgM

Five serum fractionation methods were examined with regard to their suitability for use in the demonstration of specific IgM antibodies. It was found that Protein A - Sepharose CL - 4B chromatography leads to higher IgM recovery than absorption with whole Staphylococcus aureus (58% as opposed to 40%). It is also cheaper, since this absorbent can be reused. Contamination with 2-5% IgG and about 70% IgA is encountered with both methods. Quaternary aminoethyl (QAE) - Sephadex chromatography gives excellent IgM recovery (97%) and its cost and execution time are the lowest. IgG and IgA residues are 2% and 53% respectively. Ultrafiltration results in poorer recovery of IgM (31%). However, the sample volume can be brought back to its initial value, or concentrated still further. IgG and IgA residues are 2% and 14%. The cost of the method and the time needed for its execution are relatively high. Gel chromatography is the only method to give a completely IgG- and IgA-free IgM fraction. The percentage of IgM recovered varies in accordance with the ratio between the volume of the sample and that of the column. Very high values may be obtained, but at the expense of heavy dilution. The cost is low, but the method requires a considerable amount of time. In short, none of the five methods is clearly superior to the others. Whether or not a given method is chosen will thus depend on the relative importance attached to the percentage of IgM recovered, the presence or otherwise of IgA, sample dilution, cost, and rapidity of execution.

[Toxoplasmosis: comparative serological diagnosis (direct agglutination, complement fixation, hemagglutination inhibition tests) in order to attempt to clarify the diverse periods of infection in man]

Large diffusion of human toxoplasmotic infection and consequent injuries that, sometimes, occur in pregnancy and to the newborn, have been and are principal stimulus to study and to set several diagnostic means to specify, directly or indirectly, acute infection and acquired immunity. Serological methods are, at least till now, the best diagnostic means; among these, we have selected 3 methods: IHA (Behring), CF (I.S.M.) and DA (Bio-Mérieux); with which have been tested 125 sera (selected randomly). Obtained results have been elaborated statistically according to some interpretative perspectives which have been considered the most significant. Da test, that had a propensity to understimulation of serum-positive cases, would show a good sensibility about acute or recent infections and would be positive more difficulty about past infections. IHA test, on the contrary, that showed the greatest percentage of erroneously positive results, had, on the whole, a opposite propensity, but it would seem, with some reservations, also adaptable to the search of acute infections. CF test, rather complicated and long, would seem most versatile of three tests fitting well both to the search of past immunity and to serological diagnosis of acute infection, thanks to the new TTE antigen use.

[Assay of IgA specific anti-Trichomonas vaginalis in vaginal secretions by indirect immunofluorescence]

30 vaginal secreta of women affected by acute and chronic trichomoniasis from the Gynaecological Hospital S. Anna of Turin were examined. In the same secreta the specific IgA anti Trichomonas vaginalis were detected using indirect immunofluorescence and titered on LC-Partigen IgA immunodiffusion plates. Only in 30% of these cases a correlation between immunodiffusion and fluorescence test resulted.

[Vaginal bacterial flora under normal conditions and in frequently encountered gynecological pathologies]

The bacterial flora of the female reproductive tract is a central point for the study of infectious diseases in obstetrics and gynecology. The vaginal flora contains a large variety of bacterial species, including both aerobic and anaerobic organisms. The reading of the cultures obtained from vaginal specimens in women with genital tract infections is often hard, because some organisms which are normally present in vagina may sometimes involve infectious processes. Bacterial flora was studied in 126 healthy women, in 120 with symptoms of vaginitis, in 28 with inflammation of the cervix and in 102 women previously treated for vaginitis. Comparison among the groups shows little differences in the microbial population between healthy women and patients with genital tract infections. The use of a questionnaire and the obstetrical examination were very important. As quantitative studies are fundamental, the use of methods for semiquantitative bacteriology at least have been necessary to evaluate relationships among vaginal organisms.

[The mechanism of action of aminoglycosides]

The mechanism of action of aminoglycosides depends on the inhibition of polypeptide synthesis. In fact, some of them such as Streptomycin, Sisomicin and Gentamicin are believed to cause codon misreading, by increasing the incorporation of certain aminoacids into polypeptide in the ribosome-polyribonucleotide system. Their primary site of action seems to be located in the bacterial ribosome system. Experiments with Sisomicin showed that this antibiotic arrest cell growth, aminoacid incorporation and Beta-galactosidase synthesis, but not incorporation of uracil in ribonucleic acid in E. coli cultures. When polypeptide synthesis is directed by endogenous messenger in cell-fre extracts, the antibiotic stimulates the incorporation of some amino acids into protein.

Microbiological research on specimens (dusts) drawn from the Holy Shroud

The Holy Shroud is a relic of great historical importance that, according to catholic tradition, represents the "Sudarium" i.e. the "Sindon" of Jesus Christ. By several techniques, the most recent studies try to establish a well defined dating of the Holy Shroud. In addition an attempt is also made to find out the best mean to preserve the relic. We have to this purpose performed microbiological tests on specimens (Dusts) from the Holy Shroud establishing the microbic content in various spots. Besides few exceptions, the bacteria and fungi found on the Shroud and related objects are common and spread in all the areas examined.

[Fosfomycin, lysine-fosfomycin, arginine-fosfomycin: antibacterial activity in vitro]

The antibacterial activity of NaFosfomicin and of two of its aminoacidic derivatives -Lisin-Fosfomycin and Arginin-Fosfomycin- has been determined "in vitro" as MICs and MBCs, on different groups of Bacteria. The results obtained were then statistically analyzed - according to the "t of Student" - in a comparative evaluation of the values between NaFosfomycin-Lisin-Fosfomycin (F-LF); NaFosfomycin-Arginin-Fosfomycin (F-AF); Lisin-Fosfomycin-Arginin-Fosfomycin (LF-AF). From these comparisons, the data found demonstrated no significant differences among the three compounds, for Proteus, Coliforms and Pseudomonas groups, while Salmonella and Staphylococcus Genera showed good differences (P less than 0.05) from the comparison F-AF.

[Blood protein, iron and copper, and leukocyte alkaline phosphatase in lymphoma]

An assessment was made of the importance of certain laboratory data as diagnostic and prognostic parameters in 34 cases of Hodgkin and non-Hodgkin lymphoma. The results of other workers are referred to by way of comparison.

Variability of immune response induced by bacteria treated with subminimal inhibitory concentrations of fosfomycin

Experiments were conducted to explore the possibility that bacterial strains treated with subminimal inhibitory concentrations (sub-MICs) of fosfomycin might induce immune responses different from those induced by intact, untreated bacteria. A preliminary study was done with a strain of Salmonella wien. The immune response in rabbits immunized with bacteria that had been exposed to either the sub-MIC or the minimal inhibitory concentration (MIC) of fosfomycin was compared with that in rabbits immunized with S. wien not exposed to the drug. The titers of antibody to S. wien in rabbits immunized with abnormal, sub-MIC-treated bacteria were higher than those in rabbits immunized with either MIC-treated or untreated S. wien. This difference was seen not only with the total antigen of Salmonella but also with somatic (O) and flagellar (H) antigens.

[Antibiotic resistance transmissible in "minor" Salmonella strains recently isolated in the Piedmont region]

The presence of R factors in one hundred (100 strains of Salmonella, recently isolated in Piedmont Region, has been investigated. The resistance to 9 antibiotics has been determined for these strains. 83 proved resistant to one or more antibiotics and in particular 57 of these proved to be multiresistant. Only 18 R factors were put in evidence, 13 of these belonging to Salmonella wien. The majority of the R factors found were present in strains of Salmonella isolated from healthy carriers.

[Influence of composition of the culture media on the in vitro determination of the bacterial sensitivity to sulfonamides, trimethoprim and cotrimoxazole]

The difficulties concerning the interpretation of results of susceptibility tests to sulphonamides, trimethoprim, co-trimoxazole have been investigated. The zones of inhibition produced by discs containing these drugs are peculiar since frequently they contain a light bacterial growth and small colonies. Therefore the real sensitivity or resistance of the microorganism is questionable. Susceptibility tests performed on media of different composition, have shown that the phenomenon is chiefly due to the presence in the medium of thymidine and methionine. Both the substances are end-products of the metabolic pathway on which act sulphonamides, trimethoprim, co-trimoxazole. When they are in the medium, they can be available for the bacteria in spite of the inhibition caused by the mentioned drugs.

Genetic control of Trichomonas vaginalis infection. I. Resistance or susceptibility among different mouse strains

Susceptibility of different strains of mice to infection with Trichomonas vaginalis was determined. Striking strain differences in susceptibility to T. vaginalis inoculum were observed in different mouse strains suggesting that susceptibility is under control of genes mapping mainly outside the major histocompatibility complex.